manifest: references should cover all children

To allow generic manifest walking, we define an interface method of
`References` that returns the referenced items in the manifest. The
current implementation does not return the config target from schema2,
making this useless for most applications.

The garbage collector has been modified to show the utility of this
correctly formed `References` method. We may be able to make more
generic traversal methods with this, as well.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
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Stephen J Day 2016-10-12 17:20:27 -07:00
parent e3aabfb47e
commit c9aaff00f8
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9 changed files with 81 additions and 63 deletions

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@ -12,8 +12,13 @@ import (
// references and an optional target
type Manifest interface {
// References returns a list of objects which make up this manifest.
// The references are strictly ordered from base to head. A reference
// is anything which can be represented by a distribution.Descriptor
// A reference is anything which can be represented by a
// distribution.Descriptor. These can consist of layers, resources or other
// manifests.
//
// While no particular order is required, implementations should return
// them from highest to lowest priority. For example, one might want to
// return the base layer before the top layer.
References() []Descriptor
// Payload provides the serialized format of the manifest, in addition to
@ -36,6 +41,9 @@ type ManifestBuilder interface {
// AppendReference includes the given object in the manifest after any
// existing dependencies. If the add fails, such as when adding an
// unsupported dependency, an error may be returned.
//
// The destination of the reference is dependent on the manifest type and
// the dependency type.
AppendReference(dependency Describable) error
}